1. Field of the Invention
This invention relates in general to ladders and in particular to fiberglass ladders.
2. Description of the Prior Art
Fiberglass ladders are known in the art. They have the advantage of being non-conductive of electricity, are decay and corrosion resistant, and are non-sparking. There are various designs in the prior art, some with fiberglass rails and rungs, others with fiberglass rails and metal rungs, some with hollow cores, and others with solid cores.
As far as is known, however, the rails and rungs are always formed separately, then assembled to form a ladder. Although this may be more efficient from a mass production standpoint, the interconnection or joints between the rails and rungs are troublesome. The joints must withstand loads as well as in some cases corrosive atmospheres such as found in chemical plants and refineries. Various joint designs to solve the problems are found in the following U.S. Pats.: No. 3,318,413 issued to Werner et al; No. 2,885,132 issued to Campbell; and No. 3,674,110 issued to Cooke.